Well Sean,
I guess that's a hard lesson in not taking vintage mowers to a 'shop'. Bet there's more minor bits missing now, too...
Let's face it, no shop is ever going to put in the time it would take to chase up parts for a vintage mower, particularly an uncommon one like this. No way that would pay!
Dunno why they even bothered to pull it down, unless it was just for an excuse to get some coin out of you.